Justice failed Trayvon Martin the night he was killed. We should be appalled and outraged, but perhaps not surprised, that it failed him again Saturday night, with a verdict setting his killer free.

Our society considers young black men to be dangerous, interchangeable, expendable, guilty until proven innocent. This is the conversation about race that we desperately need to have — but probably, as in the past, will try our best to avoid.

If anyone wonders why African Americans feel so passionately about this case, it’s because we know that our 17-year-old sons are boys, not men. It’s because we know their adolescent bravura is just that — an imitation of manhood, not the real thing.

The conversation we need to have is about how black men, even black boys, are denied the right to be young, to be vulnerable, to make mistakes. We need to talk about why, for example, black men are no more likely than white men to smoke marijuana but nearly four times as likely to be arrested for it — and condemned to a dead-end cycle of incarceration and unemployment. I call this racism. What do you call it?